Electrolytic Cells and Faradays Laws - UNSOLVED PRACTICE SET
Chapter: Electrochemistry | Topic: Electrolytic Cells and Faradays Laws
ELECTROLYTIC CELLS AND FARADAYS LAWS - UNSOLVED PRACTICE SET
Topic: Electrolytic Cells and Faradays Laws
Multiple Choice Questions
Q1. In an electrolytic cell, the electrode connected to the positive terminal of the battery is called the:
- Cathode
- Anode
- Salt bridge
- Reference electrode
Q2. According to Faraday's First Law of Electrolysis, the mass of substance deposited at an electrode is directly proportional to:
- The square of the current passed
- The quantity of electricity passed
- The temperature of the electrolyte
- The volume of the electrolyte
Q3. The quantity of electricity required to deposit one mole of a substance is equal to:
- nF, where n is the number of electrons, and F is Faraday's constant
- F/n
- n/F
- F²/n
Q4. In an electrolytic cell, oxidation occurs at the:
- Cathode
- Anode
- Salt bridge
- Both electrodes
Q5. According to Faraday's Second Law, when the same quantity of electricity is passed through different electrolytes, the masses of substances deposited are proportional to their:
- Atomic masses
- Equivalent masses
- Molecular masses
- Densities
Q6. The process of coating a thin layer of one metal (like zinc) over another metal (like iron) using electrolysis is called:
- Corrosion
- Electroplating
- Electrorefining
- Electrolysis of water
Short Answer Questions
Q7. State Faraday's First Law of Electrolysis. Write the mathematical expression relating mass deposited (m), current (I), time (t), equivalent weight (E), and Faraday's constant (F).
Q8. State Faraday's Second Law of Electrolysis. If the same current is passed through solutions of CuSO₄ and AgNO₃ for the same time, and 0.635 g of copper is deposited, what mass of silver will be deposited? (Given: E(Cu) = 31.75 g/equivalent, E(Ag) = 108 g/equivalent)
Q9. Differentiate between a galvanic (voltaic) cell and an electrolytic cell with respect to: (i) energy conversion, (ii) sign of ΔG, and (iii) nature of electrodes.
Q10. Draw a neat and labelled diagram of an electrolytic cell used for the electrolysis of molten NaCl. Label the anode, cathode, and electrolyte, and indicate the direction of ion movement.
Q11. What is electrorefining? Name the electrolyte and electrodes used in the electrorefining of copper. Write the reactions occurring at the anode and cathode.
Q12. A student sets up an electrolytic cell to deposit silver from AgNO₃ solution. If a current of 2 A is passed for 30 minutes, write the expression to calculate the mass of silver deposited. (Given: E(Ag) = 108 g/equivalent)
Long Answer Questions
Q13. (a) State and explain Faraday's First Law of Electrolysis with the help of a suitable example.
(b) A current of 5 A is passed through a solution of CuSO₄ for 2 hours. Calculate the mass of copper deposited at the cathode. (Given: Atomic mass of Cu = 63.5 u, Valency of Cu = 2, F = 96500 C mol⁻¹)
Q14. (a) State and explain Faraday's Second Law of Electrolysis. How does it establish a relationship between chemical equivalent and electrochemical equivalent?
(b) When the same quantity of electricity is passed through three electrolytic cells containing solutions of AgNO₃, CuSO₄, and Al₂(SO₄)₃, respectively, 1.08 g of silver is deposited. Calculate the masses of copper and aluminium deposited. (Given: E(Ag) = 108, E(Cu) = 31.75, E(Al) = 9 g/equivalent)
Q15. (a) Explain the process of electroplating with a suitable example. Why is electroplating done on iron articles used in everyday life (like bicycle handles, car bumpers, or kitchen utensils)?
(b) Describe the electrorefining of copper with a labelled diagram. Why is impure copper used as the anode and pure copper as the cathode?
Numerical / Application-Based Problems
Q16. (a) How much charge is required for the reduction of 1 mole of Al³⁺ to Al metal?
(b) A current of 1.5 A is passed through a solution of AlCl₃ for 10 minutes. Calculate the mass of aluminium deposited at the cathode.
(c) If the same charge is passed through a solution of AgNO₃, what mass of silver will be deposited?
(Given: Atomic mass of Al = 27 u, Atomic mass of Ag = 108 u, F = 96500 C mol⁻¹)
Q17. (a) A current of 3 A is passed through a solution of NiSO₄ for 40 minutes. Calculate the mass of nickel deposited at the cathode. (Given: Atomic mass of Ni = 58.7 u, Valency of Ni = 2)
(b) If the same current is passed for the same time through a solution of AgNO₃, what mass of silver will be deposited? (Given: Atomic mass of Ag = 108 u, Valency of Ag = 1)
(c) Verify your answer using Faraday's Second Law of Electrolysis.
Q18. An electrolytic cell is set up to electroplate a steel spoon with silver. The spoon is made the cathode and a pure silver rod is made the anode. The electrolyte is AgNO₃ solution.
(a) Draw a neat and labelled diagram of this electrolytic cell.
(b) Write the reactions occurring at the anode and cathode.
(c) If a current of 0.5 A is passed for 2 hours, calculate the mass of silver deposited on the spoon.
(d) Why is it important to use pure silver as the anode in this process?
(Given: Atomic mass of Ag = 108 u, F = 96500 C mol⁻¹)